As a related art valve timing control device, for example, there has been known a valve timing control device disclosed in the following Patent Document 1.
That is, the valve timing control device changes open and closing timing of an engine valve by the fact that a vane rotor that rotates in synchronization with a camshaft rotates relative to a housing that rotates in synchronization with a crankshaft then a rotation phase of the camshaft with respect to the crankshaft is changed.
The valve timing control device has a lock mechanism serving to hold a phase of the vane rotor at the time of an engine stop and secure subsequent engine startability. The lock mechanism mainly has a lock plate provided movably in a radial direction in the housing and limiting a relative rotation of the vane rotor with respect to the housing by engaging with an engagement groove that is recessed in an outer periphery of a base part of the vane rotor, and a spring interposed between the lock plate and the housing and forcing the lock plate to the base part side (center side) of the vane rotor.